Fine Tuning a 360 Magnum with a Brawler "Double Pumper"

Start with all 4 idle mixture screws at 1 turn.

What should I do about getting the secondary side “closed” then and just using the primaries?

Also, if I’m going to commit to running 93 octane all the time, should I power time it so I have the most timing it likes before continuing to tune the carb? I would imagine that would give me the best power/mpg